Process for treating carbonaceous materials



July 30, 1935. E. B. PEck 2,009,717

PROCESS FOR TREATING CARBONACEOUS MATERIALS Filed July 3, 1929 351 km wowmg"- Patented July 30, 1935 PATEN T OFFICE rnocnss 110a TltEATING CARBONACEOUS MATERIALS Edward B. Peck, Elizabeth, N. L, assignor to Standard-I. G. Company Application July 3, 1929, Serial No. 375,675

Claims.

The present invention relates to the .art of treating carbonaceous materials and more speflcally comprises a systematic method for ob taining large yields of low boiling oils from higher boiling oils with or without additionsof other carbonaceous materials. My process will be fully understood from the following description and'the drawing which illustrates appa ratus for accomplishing the process. 7

In the manufacture of low boiling hydrocar bons such as gasoline and the like from higher boiling hydrocarbons, the yield of gasoline is limited by the fact that a considerable proportion of the oil is converted into tarry or asphaltic materialand into coke. The present invention, com-j, prisesthe combination of the methods of cracking and hydrogenating the tars either formed by cracking or originally present in'the oil feed. By hydrogenation, a portion of the asphalticmaterials may be rendered suitable for further 'crack ing. My process increases the yield of gasoline and greatly decreases the yield of coke, together with other advantages which are apparent to those skilled in the art.

The drawing is a semi-diagrammatic view in elevation of an apparatus constructed according to my invention and illustrates the flow of materials. I

Referring to the drawing, reference character A denotes in general a cracking system and B denotes a hydrogenation system. The two systems may be of any preferred types, for example, they may be liquid or vapor phase as will be understood. In the preferred system which is illustrated in the drawing, numeral l denotes a cracking coil suitably arranged in a furnace setting 2. The coil discharges into a high pressure, heat insulated digestion chamber 3 from which the cracked products are withdrawn by 40 line 4 to a separator tower 5. Pipe 4 is fitted with a pressure reduction valve 6.

Tower 5 may be of any suitable design but is preferably fitted with a cooling coil 1 in its upper portion, bell cap plates 8 therebelow, and a pan 3 adapted to collect the reflux from plates 8, Pipe 4 discharges below pan 3 so that unvaporized heavy tar is collected in. the base of tower 5 from which it may be withdrawn by line I0. Vapor is removed from the top of the tower by line H which communicates with a condenser i2 and the distillate is collected in drum l3 from which gas is released by a valved line I4 and from which distillate may be removed by line l5.

Reflux produced by the cooling coil 1 washes 5 down plates 8 and is collected in pan 9 from which it may be removed by pipe l6 to an accumulator tank IT. .The accumulated oil maybe then recirculated, together with fresh oil and/or otherv suitable stock produced win the hydrogenation step, as will appear below, to coil I and drum 5 3 for further cracking by way of pipe l8, pump I3, coil 1 and pipe 20.

Tar may be withdrawn from the system byline l0 but itis preferably forced by pump 2| through line 22 toa disintegrator 23 in which carbonace'ous material such as coal and the. like may be finelyground and mixed with the oil. A high pressure pump 24 picks up thetar or other oil from line 22 an'd forces it through a heating coil 25 and into a hydrogenation chamber 26. The hydrogenation chamber is adapted to withstand extremely hi'gh internalj' pressure; vfor example 200 atmospheresor higher, and is arranged with a suitable stirring mechanism 21 or its equivalent. The drum may be heated internally or maintained at the operating temperature by the heat of the reaction itself; or by the addition of regulated quantities of CO: to the hydrogen gas, but it is preferable to maintain its temperature by withdrawing a part of the oil by line 28 and forcing it by pump 29 back to .drum 26 by way of coil 25. Gas rich in hydrogen is supplied by line 30, compressed by compressor 3| and fed from high pressure manifold 32 to coil 25 by means of branch pipe 33 and to drum 26 by pipe 34.

Vapor and gas from drum 26 may be conducted by line 35 to a vapor phase converter 36 which is provided with suitable catalyst 31 or it may be shunted around converter 36 by line 40. Additional' hydrogen is admitted to the converter from manifold 32 by means of line 38. The converter may be heated internally by electrical heaters (not shown) or it may be heated by heat added to the additional hydrogen by a heater 39. Whether the vapor and gas passes thru converter 36 or not they are then passed by line 4| to a suitable separator system.

7 The separator system may be of any suitable design but preferably a condenser is provided first and it may be in the form of a tower 42 fitted with plates or other packing and a coil 43 for cooling its upper portion. Gas flowing from the top of the tower under high pressure is then conducted by line 44 to compressor 3| and back to high pressure manifold 32, but it is preferable to pass the recirculated hydrogen thru a purifier 45.

Condensate from tower 42 is conducted by line 46 which is fltted with a reduction valve 41, to a tower 43. This tower may be fitted with plates and is supplied with a cooling coil 49 at the top and a heating coil 50 at its base. Light oil vapor is conducted from the top of the tower by vapor line 5! to condenser 52 and separator drum 53 from which gas is released by line 54 and distillate is removed by line 55. Distillate from drums l3 and 53 may be blended in a common storage tank (not shown) if desired, or the oils may be separately finished and blended later as will be understood.

Condensate from the base of tower 46 which comprises the heavier fractions of the distillate from drum 261s forced by pump 56 through line 51 to accumulator tank I! for cracking as has been described above. Fresh oil is supplied by line 58 and forced by pump 59 through coils l9 and 43 for preheat and into drum II by line 66 or into line 22 by 6!. It will be recalled that the oil caught in pan 9 of the cracking coil bubble tower 5 may be recirculated through the cracking coil I and drum 3, if desired; however, the oil from tower 9 may be fed to the hydrogenationcoil 25 and drum "by means of line 62 and pump 63 which are converted into line 22. In an alternative manner the clean pan stock may be passed by line 62 and pump 63 through pipe 64 and into the vapor line 35 communicating with the vapor phase drum 36. The oil may be heated or vaporized before forcing it into line 35 by a suitable heater 65. In the same manner condensate from tower 48 may be fed to heater 65 and drum 36 either alone or admixed with condensate from pan 9 in column 5.

It will be understood that my proces may be operated in several alternative methods according to the character of the feed stock and other conditions, but in any case my invention comprises a combination of cracking and hydrogenation steps. Cracked oils such as tar and/or recycle stock from pan 9 are subjected to hydrogenation treatment, whereby light oil and an improved cracking stock is produced. The cracking stock is usually returned to the cracking step. The fresh oil may be fed either to the cracking or to the hydrogenation step, depending on the nature of the oil. If a heavy asphaltic oil is used or one containing a large quantity of sulphur, it is generally desirable to feed it to the hydrogenation unit to produce therefrom a superior cracking stock and at the same time remove a large part of the sulphur bodies. On the other hand, where reasonably good grades of oil are being treated, it is preferable to feed the cracking system.

The cracking unit may be run in the ordinary manner recirculating the heavy oil condensate and feeding tar to the hydrogenation unit, but it is often preferable to feed the heavy condensate to the hydrogenation unit. This may be done as pointed out above either by passing it with or without tar through coil 25 and into drum 26, but the heavy cracked condensate may be injected into the vapors leaving drum 26 and be treated in converter 36. This may be satisfactorily done without using drum 26 but vaporizing the oil in heater 65 and passing vapor therefrom into the converter. There are other advantageous arrangements by which my process may be utilized.

The conditions for cracking and hydrogenation are in general familiar and may be varied considerably. The drum temperature in both operations is preferably in the range of 750 to 950 F. and in the vapor phase converter the temperature is from about 850 to 1100 F. or higher but in general 850 to 970 F. is preferred. The pressure during cracking is preferably from 6 to '70 atmospheres although it may be either lower or higher. During hydrogenation in the liquid phase pressure above about 50 atmospheres is used and is preferably about 200 atmospheres while in the vapor phase it may be about the same or may be as low as about 25 atmospheres.

Catalysts maybeusedtoassistin thehydrogenation and may be suspended in the oil subjected to liquid phase hydrogenation and recirculated through the heating coil without diniculty. A mixture of chromium and molybdenum oxides is an example of a satisfactory catalyst although others may be used.

Hydrogen or a gas rich in free hydrogen is passedinto coil 25 withtheoilandmay alsobe added to the drum 26 in considerable excess of the quantity required to actually combine with the oil. Ifthe vapor phase converter is used it is preferable to add fresh hydrogen at this point also. The eiiiuent hydrogen is recompressed and re-' turned to the process but it is preferable to provide some purification such as an oil wash under high pressure to remove or reduce the content of hydrocarbon gas and hydrogen sulphide- An alkali wash may be included.

My process, while particularly adapted for crude or reduced crude petroleum, may be used with gas tars, coal tars, refinery residues, shale oil, pitches, and the like and coal or other solid materials such as asphalts, bitumens and the like may be added to the oil. Itis not necessary to add fresh oil to the process when coal or the like is used after a supply of heavy oil is produced from the coal.

My invention is not to be limited to any theory of the mechanism of the process nor by any illustrative example but only by the following claims in which I wish to claim all novelty inherent in the process.

I claim:

1. An improved process for producing valuble gasoline fractions from higher boiling hydrocarbons which comprises subjecting the higher boiling hydrocarbons to the action of hydrogen at a temperature between 750 and 950 F. and under a pressure in excess of 50 atmospheres, removing vapors formed in this treatment, subjecting the vapors to treatment with additional hydrogen at a higher temperature, fractionating the product of this treatment, recovering gasoline fractions therefrom, subjecting the reflux condensate from the fractionation to cracking, fractionating the products of cracking, recovering a reflux condensate therefrom and introducing this condensate into the vapors from the first hydrogen treatment.

2. Process according to claim 1 in which the higher boiling hydrocarbons used as the initial material comprise heavy asphalt containing hydrocarbon oil.

3. Process according to claim 1 in which both hydrogen treatments are carried out in the presence of a catalyst immune to sulfur poisoning.

4. An improved process for producing valuble gasoline fractions from higher boiling hydrocarbon oil which comprises subjecting the higher boiling hydrocarbon oilto treatment with hydrogen at a temperature between 750 and 950 F. and under pressure in excess of 50 atmospheres, removing vapors formed in this treatment, subjecting a portion of these vapors to treatment with additional hydrogen at a higher temperature,

passing these treated vapors together with the 7 into the vapors from the first hydrogen treatment,

5. Process according to claim 4 in which the reflux condensate from the cracking step is heated prior to its introduction into the vapors from the first hydrogen treatment.

EDWARD B. PECK. 

